//! SSL工具
//! 
//! 提供SSL/TLS相关功能

use std::time::{SystemTime, UNIX_EPOCH};
use url::Url;

/// SSL错误类型
#[derive(Debug, thiserror::Error)]
pub enum SslError {
    #[error("Connection failed: {0}")]
    ConnectionFailed(String),
    #[error("Certificate verification failed: {0}")]
    CertificateError(String),
    #[error("Invalid URL: {0}")]
    InvalidUrl(String),
    #[error("Network error: {0}")]
    NetworkError(#[from] std::io::Error),
}

pub type SslResult<T> = Result<T, SslError>;

/// SSL证书信息
#[derive(Debug, Clone)]
pub struct CertificateInfo {
    pub subject: String,
    pub issuer: String,
    pub valid_from: u64,
    pub valid_to: u64,
    pub is_valid: bool,
    pub fingerprint: String,
}

/// 验证SSL证书
/// 
/// 这是一个简化的实现，仅用于演示目的
/// 生产环境中应使用专业的SSL/TLS库
/// 
/// # Examples
/// ```
/// use librarys::network::verify_ssl_cert;
/// 
/// // 注意：这需要网络连接
/// // let is_valid = verify_ssl_cert("https://www.google.com").unwrap();
/// // assert!(is_valid);
/// ```
pub fn verify_ssl_cert(hostname: &str) -> SslResult<bool> {
    // 解析URL
    let url = Url::parse(hostname)
        .map_err(|_| SslError::InvalidUrl(format!("Invalid URL: {}", hostname)))?;
    
    let host = url.host_str()
        .ok_or_else(|| SslError::InvalidUrl("No host in URL".to_string()))?;
    
    let port = url.port().unwrap_or(443);
    
    // 简化实现：尝试连接到主机
    use std::net::{TcpStream, ToSocketAddrs};
    use std::time::Duration;
    
    let socket_addr = format!("{}:{}", host, port)
        .to_socket_addrs()
        .map_err(|e| SslError::ConnectionFailed(format!("DNS resolution failed: {}", e)))?
        .next()
        .ok_or_else(|| SslError::ConnectionFailed("No valid address found".to_string()))?;
    
    // 尝试TCP连接（这里只是检查连接性，不是真正的SSL验证）
    let _stream = TcpStream::connect_timeout(&socket_addr, Duration::from_secs(10))
        .map_err(|e| SslError::ConnectionFailed(format!("Connection failed: {}", e)))?;
    
    // TODO 这里应该进行SSL手动和证书验证，但为了简化只返回true
    // 在实际应用中，应该使用专业的TLS库如rustls或native-tls
    Ok(true)
}

/// 获取SSL证书信息
/// 
/// 这是一个模拟实现，返回模拟数据
/// 
/// # Examples
/// ```
/// use librarys::network::get_certificate_info;
/// 
/// // let cert_info = get_certificate_info("https://www.google.com").unwrap();
/// // assert!(!cert_info.subject.is_empty());
/// ```
pub fn get_certificate_info(hostname: &str) -> SslResult<CertificateInfo> {
    // 解析URL
    let url = Url::parse(hostname)
        .map_err(|_| SslError::InvalidUrl(format!("Invalid URL: {}", hostname)))?;
    
    let host = url.host_str()
        .ok_or_else(|| SslError::InvalidUrl("No host in URL".to_string()))?;
    
    // 这里应该从实际的SSL证书中获取信息，但为了简化返回模拟数据
    let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
    let valid_from = now - 86400 * 30; // 30天前
    let valid_to = now + 86400 * 365; // 1年后
    
    Ok(CertificateInfo {
        subject: format!("CN={}", host),
        issuer: "CN=Simulated CA".to_string(),
        valid_from,
        valid_to,
        is_valid: true,
        fingerprint: "00:11:22:33:44:55:66:77:88:99:AA:BB:CC:DD:EE:FF".to_string(),
    })
}

/// 检查证书是否过期
/// 
/// # Examples
/// ```
/// use librarys::network::is_certificate_expired;
/// 
/// let cert_info = librarys::network::get_certificate_info("https://example.com").unwrap();
/// let is_expired = is_certificate_expired(&cert_info);
/// assert!(!is_expired); // 模拟证书不会过期
/// ```
pub fn is_certificate_expired(cert_info: &CertificateInfo) -> bool {
    let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
    now > cert_info.valid_to
}

/// 检查证书是否即将过期（默认30天内）
/// 
/// # Examples
/// ```
/// use librarys::network::is_certificate_expiring_soon;
/// 
/// let cert_info = librarys::network::get_certificate_info("https://example.com").unwrap();
/// let is_expiring = is_certificate_expiring_soon(&cert_info, 30);
/// // 根据模拟数据的设置，这个值可能为true或false
/// ```
pub fn is_certificate_expiring_soon(cert_info: &CertificateInfo, days: u64) -> bool {
    let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
    let threshold = now + (days * 86400);
    cert_info.valid_to <= threshold
}

/// 获取证书的剩余有效天数
/// 
/// # Examples
/// ```
/// use librarys::network::get_certificate_days_until_expiry;
/// 
/// let cert_info = librarys::network::get_certificate_info("https://example.com").unwrap();
/// let days_left = get_certificate_days_until_expiry(&cert_info);
/// assert!(days_left > 0); // 模拟证书还有很多天
/// ```
pub fn get_certificate_days_until_expiry(cert_info: &CertificateInfo) -> i64 {
    let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
    let seconds_left = cert_info.valid_to as i64 - now as i64;
    seconds_left / 86400
}

/// 验证主机名与证书是否匹配
/// 
/// # Examples
/// ```
/// use librarys::network::{get_certificate_info, verify_hostname_match};
/// 
/// let cert_info = get_certificate_info("https://example.com").unwrap();
/// let matches = verify_hostname_match(&cert_info, "example.com");
/// assert!(matches); // 模拟证书总是匹配的
/// ```
pub fn verify_hostname_match(cert_info: &CertificateInfo, hostname: &str) -> bool {
    // 简化实现：检查证书中是否包含主机名
    cert_info.subject.contains(hostname) || 
    cert_info.subject.contains(&format!("CN={}", hostname))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_certificate_info_structure() {
        let cert_info = CertificateInfo {
            subject: "CN=example.com".to_string(),
            issuer: "CN=Test CA".to_string(),
            valid_from: 1000000000,
            valid_to: 2000000000,
            is_valid: true,
            fingerprint: "AA:BB:CC:DD".to_string(),
        };
        
        assert_eq!(cert_info.subject, "CN=example.com");
        assert!(cert_info.is_valid);
    }

    #[test]
    fn test_certificate_expiry_check() {
        let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
        
        let expired_cert = CertificateInfo {
            subject: "CN=expired.com".to_string(),
            issuer: "CN=Test CA".to_string(),
            valid_from: now - 86400 * 100,
            valid_to: now - 86400 * 10, // 10天前过期
            is_valid: false,
            fingerprint: "AA:BB:CC:DD".to_string(),
        };
        
        assert!(is_certificate_expired(&expired_cert));
        
        let valid_cert = CertificateInfo {
            subject: "CN=valid.com".to_string(),
            issuer: "CN=Test CA".to_string(),
            valid_from: now - 86400 * 30,
            valid_to: now + 86400 * 365, // 1年后过期
            is_valid: true,
            fingerprint: "AA:BB:CC:DD".to_string(),
        };
        
        assert!(!is_certificate_expired(&valid_cert));
    }

    #[test]
    fn test_hostname_verification() {
        let cert_info = CertificateInfo {
            subject: "CN=example.com".to_string(),
            issuer: "CN=Test CA".to_string(),
            valid_from: 1000000000,
            valid_to: 2000000000,
            is_valid: true,
            fingerprint: "AA:BB:CC:DD".to_string(),
        };
        
        assert!(verify_hostname_match(&cert_info, "example.com"));
        assert!(!verify_hostname_match(&cert_info, "other.com"));
    }

    #[test]
    fn test_days_until_expiry() {
        let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
        
        let cert_info = CertificateInfo {
            subject: "CN=test.com".to_string(),
            issuer: "CN=Test CA".to_string(),
            valid_from: now - 86400 * 30,
            valid_to: now + 86400 * 30, // 30天后过期
            is_valid: true,
            fingerprint: "AA:BB:CC:DD".to_string(),
        };
        
        let days_left = get_certificate_days_until_expiry(&cert_info);
        assert!(days_left >= 29 && days_left <= 30);
    }

    // 注意：以下测试需要网络连接，在CI/CD环境中可能需要禁用
    #[test]
    #[ignore]
    fn test_ssl_verification_real() {
        let result = verify_ssl_cert("https://www.google.com");
        // 这个测试可能会因为网络问题失败，所以被标记为忽略
        if result.is_ok() {
            assert!(result.unwrap());
        }
    }

    #[test]
    #[ignore]
    fn test_get_certificate_info_real() {
        let result = get_certificate_info("https://www.google.com");
        if result.is_ok() {
            let cert_info = result.unwrap();
            assert!(!cert_info.subject.is_empty());
            assert!(!cert_info.issuer.is_empty());
        }
    }
}